Die for forming and knurling sheet metal can tops



Patented Oct. 24, 1939 UNITED" STATES PATENT OFFICE DIE FOR FORMING AND KNURLING SHEET METAL CAN TOPS Application December 5, 1936, Serial No. 114,511

5 Claims.

The invention relates generally to metal punching and drawing apparatus and particularly to die structures for such apparatus capable of forming can covers including hand grip knurled portions by a simple drawing and pressing operation.

I am aware that can cover forming devices have heretofore been provided which are capable of forming covers or closures equipped with hand grip knurling, but it'has been the practice heretofore to form such knurling by rotating the cover in engagement with the knurl forming devices. Such forming equipments lack the simplicity and efliciency of our improved die structure.

The invention has for its object to provide an improved die structure embodying novel male and female shaping units capable at each thrust or movement together, of cutting a cover or closure from a metal sheet, and drawing and pressing it to form the cover top including a depending skirt or flange and hand grip knurling in the skirt and extending into the cover top surface with no portion thereof projecting beyond the outside diameter of said skirt.

With the above and other objects in view that will hereinafter appear, the nature of the invention will be more clearly understood by following the description, the appended claims, and the several views illustrated in the accompanying drawing.

In the drawing:

Figures 1 and 2 are central vertical cross sections of the die structure units embodying the female and male forming elements respectively.

Figure 3 is a fragmentary vertical cross section and part elevation of a cover formed by our improved die structure.

Figure 4 is a fragmentary vertical cross section illustrating the die structure units engaged in the 7 formation of a can cover.

Figure 5is a View similar to Figure 4 illustrating the ejection of a formed can cover.

In the drawing, in which like numerals of reference indicate like parts in all of the figures, we have disclosed only themale element and female element units which comprise the subject matter of our invention. Any suitable form of supporting and actuating devices such as are customarily employed in presses may be used in conjunction with these units, and the construction and operation of such devices is so well known to workers in the art that it is considered unnecessary to disclose and describe them in detail herein.

The male element unit, disclosed in Figure 2, includes a base plate 5 and an upstanding flanged collar or ring 6 centered in the annularrecess 1 I formed in the base plate and having its flange secured to said plate as at 8. The member 6 includes a cutting edge 9 and an overhanging shoulder I 0.

The base plate 5 also has a central recess H in which the male forming element 12 is secured as at IS. The element l2 includes a center bore or seat H1 in which an embossing plate I5 is removably secured as at IS. The upper face of the removable and replaceable embossing plate lies flush with the upper edge of the male element I2 and, in practice, is equipped with any approved design (not shown) intended to be imparted to the formed can cover.

At its upper peripheral surface the male element I2 is reduced in diameter so as to provide a cover flange or skirt clearance I1 the uppermost edge portion of which is equipped with spaced grooves 18 extending through the top face;

and providing intervening knurl forming ribs. The ribs parallel the axis of the die unit and are wholly confined within the peripheral outline of the clearance portion I1. An annular rib forming groove I9 is provided in the upper surface:

of the male element l2.

A cover flange anvil ring 20 surrounds the male element 12 and has a moving fit in the space between said element and the collar 6. The ring 20 includes an extended abutment shoulder 2| engageable with the overhanging shoulder H] of the collar 6 to limit upward movement of the ring to a position flush with the cutting edge 9. Guide pins 22 depend from the ring 20 and pass through bores 23 provided in the plate 5. Any approved spring means such as is indicated at 24 may be employed to normally hold the abutment shoulders 2| and ID in engagement.

The female element unit, shown in Figure 1, includes a body 25 to which an overhanging flange plate 26 is secured as at 21. The body has an annular seat 28 on which the female element or draw ring 29 is dowel positioned as at 39. A shouldered cutting and drawing ring 3|, dowel positioned at 32 upon the annular body seat 33,?

serves to secure the draw ring 29 in position and is in turn removably secured to the body 25 as at 34. It will be noted that the inside and outside diameters of the ring 3| coincide with those of the male element unit ring 20.

The inside diameter of the draw ring 29 is smaller than the inside diameter of the cutting and drawing ring 3| to a degree substantially equivalent to the gage of the metal of which the can covers are to be made, and the overhang thus- 1 abutment head on the plunger.

provided is equipped with knurl forming groove and rib equipment adapted to cooperate with the equipment l8 of the male element unit previously described. The securing means l3 of the male element unit and the dowel equipment 30 of the female element unit serve to assure proper registry of the knurl forming parts [8 and 35 at all times.

A forming and ejecting head 36 is slidably mounted within the draw ring 29 and is carried by a plunger 3! movable in an axial bore 38 formed in the body 25 and the hub extension 39 of that body. The head 36 is normally held in the position shown in-Figure 1 by a spring 40 interposed between the hub extension and an An annular bead forming rib 4! is provided on the head 36 for 00- operating with the groove I9 of the male element (unit, and in the center bore or seat 42 of said head an embossing plate 43 is removably secured as at 44. The plate 43 is the same in design and purpose as the male element unit plate [5 previously described. Upon the peripheral die surface formed compositely by the ring 3| and the body '25, a flanged stripping ring 45 is slidably mounted. This stripping ring is supported upon limiting pins 45, and spring equipment A? interposed between the ring flange and the overhanging plate 26 serves to yieldably hold the ring in the position shown in Figure 1. 1

In operation, as the female element unit descends toward the can cover blank or sheet resting upon the male element unit, the ring 3i will engage the blank or sheetand grip it against the anvil ring 29. Upon continued movement of the now engaged parts the ring SI and the cutting edge 9 will act to cut the sheet or trim off the excess of the cover blank metal, and the ring 20 of the male unit and the ring d5 of the female unit will be caused to recede downwardly and upwardly, respectively, from the positions shown in Figures 2 and l.

As the ring 3| forces the anvil ring 25 to recede farther into the annular groove of the male element die unit, the inner edge and face of the ring ,3! will start the drawing of the cover blank over the male element l2 and ultimately complete the formation of the cover skirt or flange in the clearance ll provided in said element. During the final stage of the skirt formation the knurl formingequipments i8 and 35 interengage to form the knurling, and as the forming elements finally seat, the cover top bead is formed by the equipments l9 and 4|, and the designs (not shown) on the embossing plates l5 and 43 cooperate to emboss the top of the cover in the manner desired. The state of completion of the cover is shown in Figure 4.

After completion of the cover the die units are moved apart and as the ring 3! of the female element unit is being withdrawn from the annular groove of the male element unit the stripper ring 45 will strip off the excess blank metal and hold it against the cutting edge 9, as shown at 46 in Figure 4. Being frictionally embraced by the female element forming parts, the completed cover is withdrawn with the female unit.

At a suitable time during the separative movement of the female unit, or at the completion of this movement, the plunger 3? is actuated, in any well known manner, to depress the ejector head 35 and eject the completed can cover.

A fragment of a completed cover is shown in Figure 3 in which the cover top is designated 49.

The bead groove formed in the cover is designated 50, the flange or skirt 5|, and the alternate ribs and grooves constituting the knurling 52. It will be noted that no portion of the knurling extends beyond the outside diameter of the cover flange or skirt 5i, and that the grooves forming the knurling extend through the cover top surface portion. Knurling of this character can be formed in our improved die structure by a simple drawing and pressing operation accomplished by a relative movement of the die units in a direction at right angles to the plane of the cover.

It is thought that from the foregoing description, considered in connection with the accompanying drawing, the construction, the manner of use, and the advantages of our improved die structure will be apparent to those skilled in the related art.

I claim:

1. In a die structure, a female can cover forming unit comprising, a body having an annular seat, a knurl drawing ring positioned on the seat,

and having knurl forming grooves and spaced ribs in its lower internal edge portion, and a shouldered ring removably secured to the body for securing the drawing ring on its seat and having an auxiliary drawing surface paralleling the axis of the drawing ring and aligned with the bottom surfaces of the grooves thereof.

2. In a die structure, a female can cover forming unit comprising, a body having an annular seat, a knurl drawing ring positioned on the seat and having knurl forming grooves and spaced ribs in its lower internal edge portion, a shouldered ring removably secured to the body for securing the drawing ring on its seat and having an auxiliary drawing surface paralleling the axis of the drawing ring and aligned with the bottom surfaces of the grooves thereof, and a cooperating male member receivable in the shoulder ring in metal drawing relation thereto and having spaced grooves in the peripheral wall and extending through the end thereof for cooperating with the female unit ribs.

3. In a die structure, a female can cover forming unit comprising, a body having an annular seat, a knurl drawing ring positioned on the seat and having knurl forming grooves and ribs in its lower internal edge portion, a shouldered ring removably secured to the body for securing the 5 drawing ring on its seat and having an auxiliary drawing surface paralleling the axis of the drawing ring and aligned with the bottom surfaces of the grooves thereof, a stripper ring-surrounding and slidable on the shouldered ring, spring and limiting pin equipment for normally positioning the stripper ring with an end thereof aligned with the drawing surface equipped end of the shouldered ring, and a shaping and ejecting head movably mounted within the drawing ring.

4. In a die structure, a female can cover forming unit comprising, a body having an annular seat, a knurl drawing ring positioned on the seat and having knurl forming grooves in its lower internal edge portion, a shouldered ring removably secured to the body for securing the drawing ring on its seat and having an auxiliary drawing surface paralleling the axis of'the drawing ring and aligned with the bottom surfaces of the grooves thereof, a shaping and ejecting head movably mounted within the drawing ring and including a recess and an embossing plate removably mounted therein; and a cooperating male unit comprising a base, a circular male element secured upon and extending above the base and having formed in its upper peripheral wall an annular cover skirt clearance recess and spaced knurl forming grooves extending through its upper end for cooperating with the female unit grooves and an end recess and an embossing plate removably mounted therein in position for upposing the female unit embossing plate.

5. In a die structure, a female can cover forming unit comprising, a body having an annular seat, a knurl drawing ring positioned on the seat and having knurl forming grooves in its lower internal edge portion, a shouldered ring removably secured to the body for securing the drawing ring on its seat and having an auxiliary drawing surface paralleling the axis of the drawing ring and aligned with the bottom surfaces of the grooves thereof, a shaping and ejecting head movably mounted within the drawing ring and including a recess and an embossing plate removably mounted therein, and a cooperating male unit comprising a base, a circular male element secured upon and extending above the base and having formed in its upper peripheral wall an an- I nular cover skirt clearance recess and spaced knurl forming grooves extending through its upper end for cooperating with the female unit grooves and an end recess and an embossing plate removably mounted therein in position for opposing the female unit embossing plate, a waste severing ring mounted on the base surrounding the male element in spaced relation to form therebetween an annular groove to receive the shouldered ring on the female unit for waste severing cooperation with the severing ring, an anvil ring slidably mounted in the annular groove and displaceable by movement of the shouldered ring into said annular groove, said severing and anvil rings having complementary abutment shoulders, and means for yieldably holding the abutment shoulders in engagement to normally position the rings in end alignment; a waste stripper ring surrounding and slidable on the shouldered ring, and spring and limiting pin equipment for normally positioning the stripper ring with an end thereof aligned with the drawing surface equipped end of the shoulder ring.

WALTER G. PLUMB. 

